Device of the kind comprising a highpower klystron with getter ion pump connected thereto



April 5, 1966 w, SCHM|DT A 3,244,933

DEVICE OF THE KIND COMPRISING A HIGH-POWER KLYSTRON WITH GETTER ION PUMP CONNECTED THERETO Filed Aug. 21, 1962 2 Sheets-Sheet l INVENTOR w. scnmo'r 6. w SCHUMANN Fig. 5

BY AGEN Aprll 5, 1966 w, sc T 3,244,933

DEVICE OF THE KIND COMPRISING A HIGH-POWER KLYS'IRON WITH GETTER ION PUMP CONNECTED THERETO Filed Aug. 21, 1962 2 Sheets-Sheet 2 Fig.4

INVENTOR W. SCHMID G. W SCHUMANN 2 g #6 AGENT United States Patent M 3,244,933 DEVICE OF THE KIND COMPRISING A HIGH- POWER KLYSTRON WITH GETTER ION PUMP CONNECTED THERETO Wolfgang Schmidt, Hamhurg-Uthmarschen, and Gerhard Werner Schumann, Hamburg, Germany, assignors to North American Philips Company, Inc., New York, N .Y., a corporation of Delaware Filed Aug. 21, 1962, Ser. No. 218,357 Claims priority, application Germany, Aug. 24, 1961, P 27,760 3 Claims. (Cl. 3155.39)

The invention relates to a device comprising a highpower klystron with an annexed getter ion pump, in which the resonant cavities of the klystron are at ground potential.

In a known discharge tube having an incorporated ion pump, this pump is housed in the earthed part thereof.

There are known getter ion pumps in which the anode is formed by a ring or a honey comb between two cathode plates, which intersects a magnetic field at right angles to the anode surface. The cathode usually constitutes at the same time the housing of the getter ion pump.

The use of said known getter ion pump in a high-power kylstron would give rise to various difficulties. It is usual that the getter ion pump is arranged in the grounded part, the resonant cavities or the collector. However, no space is available there, not even for the magnets of the pump, which are disposed outside the vacuum. This would require a comparatively long pump tube between the klystron and the getter ion pump, which tube, owing to its high resistance, does not permit the use of a low pressure under all conditions.

The invention has for its object to provide a device which permits using an advantageous combination of a klystron and a pump.

According to the invention in a device having a highpower klystron with an annexed getter ion pump having an anode lying between two cathode plates, which intersects a magnetic field at right angles to the anode surface, the resonator cavities of the klystron being at ground potential, the getter ion pump is directly arranged on the cathode housing of the klystron, which housing is at negative potential to ground while the anode of the pump is connected to a voltage divider between the cathode housing and earth.

The device according to the invention has the advantage that no separate voltage source for the anode of the pump is required, since it is connected to the voltage divider between ground and the cathode envelope. Moreover, the pump is arranged near that tube portion to which the ions travel under the action of the potential differences prevailing at the tube. This is even the case if the cathode current is zero, since for example the modulation anode usually arranged between the cathode and the resonator cavities is at cathode potential. This has advantages in degassing the cathode. By arranging the ion pump at the bottom of the cathode housing and by housing the magnets of the pump in a substantially completely closed weak-magnetic envelope, the pump magnetic field has no influence on the electron-optical system of the klystron.

The invention will be described more fully with reference to the drawing, in which FIGS. 1 and 2 are a sectional view and an elevation respectively of an annexed ion pump with the electric connection and FIG. 3 shows a magnetic system for the pump in a partly developed perspective view and FIG. 4 is a sectional view of an ion pump arranged in the magnetic system.

FIG. 5 is a schematic view of a klystron with an ion pump connected to the cathode housing.

3,244,933 Patented Apr. 5, 1966 Referring now to FIGS. 1 and 2 reference numeral 1 designates the connecting flange of the cathode housing 3, to which the flange 5 of the ion pump 7 is soldered. The known pump 7 consists of an annular anode 9, which is surrounded by the pump housing 11. The walls 15 of the pump housing 11 are covered with titanium plates 17, which constitute the cathode of the pump. Titanium is excellently suitable for the absorption of gas. The anode connection 19 is taken to the outside in a vacuum-tight manner by means of the insulator 18. The anode is connected to the contact 21 of the voltage divider 23, formed by the resistors 24 and 25, which are connected in series between the cathode housing and earth. The resistors 24 and 25 are chosen so that with a potential of the cathode housing 3 to earth of -18 kv. the anode 13 is at 15 kv., so that it has a positive voltage of 3 kv. with respect to the pump housing and the cathode. A separate voltage source may therefore be dispensed with.

In FIGS. 3 and 4 reference numeral 27 designates sintered, oxidic permanent-magnetic discs housed in a weak-magnetic envelope 29. The length of the air-gap corresponds to the size of the pump 7. The envelope 29 can be slipped onto the pump by means of a recess 33 so that after the disposition of the weak-magnetic lid 35 no leakage field of any importance can any longer occur.

What is claimed is:

1. In combinationa klystron comprising a cathode, cavity resonators, a collector, and a housing for said cathode, means to ground the cavity resonators, an ion pump comprising an envelope of magnetic material, a pair of cathodes in opposed spaced relationship within the envelope, and an anode between said cathodes, means to provide a magnetic field normal to the surface of the anode, means to mount the ion pump on the housing of the cathode to evacuate directly the klystron by withdrawing ions moving toward the cathode of the klystron, means to connect the cathode hon-sing through a voltage dividing network to ground potential, and means to connect the anode of the ion pump to a point in the voltage dividing network intermediate the cathode housing of the klystron and ground potential.

2. In combination a klystron comprising a cathode, cavity resonators, a collector, and a housing for said cathode, means to ground the cavity resonators, an ion pump comprising an envelope of magnetic material, a pair of titanium cathodes in opposed spaced relationship within the envelope, and an anode between said cathodes, means to provide a magnetic field normal to the surface of the anode, means to mount the ion pump on the housing of the cathode to evacuate directly the klystron by withdrawing ions moving toward the cathode of the klystron, means to connect the cathode housing through a voltage dividing network to ground potential, and means to connect the anode of the ion pump to a point in the voltage dividing network intermediate the cathode housing klystron and ground potential.

3. The combination as claimed in claim 2 in which the magnetic field is produced by sintered oxidic magnets mounted within the envelope of the ion pump.

References Cited by the Examiner UNITED STATES PATENTS 2,131,897 10/1938 Malter 3137 X 2,988,657 6/1961 Klopfer et al. 313--7 3,094,639 6/ 1963 Iepsen 313-7 FOREIGN PATENTS 6, 123 12/1960 Great Britain.

JOHN W. HUCKERT, Primary Examiner.

DAVID N. GALVIN, Examiner. 

1. IN COMBINATION A KLYSTRON COMPRISING A CATHODE, CAVITY RESONATORS, A COLLECTOR, AND A HOUSING FOR SAID CATHODE, MEANS TO GROUND THE CAVITY RESONATORS, AN ION PUMP COMPRISING AN ENVELOPE OF MAGNETIC MATERIAL, A PAIR OF CATHODES IN OPPOSED SPACED RELATIONSHIP WITHIN THE ENVELOPE, AND AN ANODE BETWEEN SAID CATHODES, MEANS TO PROVIDE A MAGNETIC FIELD NORMAL TO THE SURFACE OF THE ANODE, MEANS TO MOUNT THE ION PUMP ON THE HOUSING OF THE CATHODE TO EVACUATE DIRECTLY THE KLYSTRON BY WITH- 